Category Archives: Valve Gear

Richard Coleby

As fabrication finally gets underway we’ve been critically assessing the designs and pouring over reports of the engine’s performance whilst in service to identify flaws and investigate where and how to incorporate the best of modern practice while remaining as true as possible to the original design. To this end Ted Talbot, Peter Stanton and Jamie Keyte among others are dedicating their invaluable time and expertise to the task, and we hope to report more on their involvement as the project progresses.

A task of building a new-build of an extinct class is a fine balancing act – that is, how to be true to the original design while ensuring that any design flaws when identified, aren’t repeated or are at least mitigated. In the case of the LNWR George the Fifth class, we are dealing with a design that is over 100 years old. We have the benefit of hindsight arising from reports into the service life of the class (which themselves have to be investigated for their veracity or potential bias – take the reports of ‘flimsy frames‘ for example, which appears to have been unwarranted) and of 100 years of subsequent practice in locomotive engineering specifically and engineering and metallurgy more generally.

And so in addition to the tremendous pool of expertise and knowledge mentioned above we are also pleased to announce the critical assistance of Derby-trained Richard Coleby who has kindly agreed to investigate reports of possible valve-gear errors in the original George the Fifth design. Richard’s impressive resume includes serving an Engineering Apprenticeship at Derby Loco Works in the final years of steam during which he gained an in-depth knowledge of the repair and maintenance of steam locomotives.

After leaving BR in 1969 he established a partnership dedicated to building large scale miniature steam locomotives and was responsible for the design of several engines including the famous Stapleford Nickel Plate Berkshire (at the time the most powerful 1/5th scale locomotive in the world) and the 59 class Garratt now residing at the NRM.

In the 1980s he was responsible for a rebuild of the Stapleford Curwen Atlantic ‘John of Gaunt’ which included many features designed to reduce maintenance requirements, such as the enclosed toary-driven valve gear, roller crossheads and big-ends and balanced slide valves. In 2009 he led the project to build ‘Norfolk Heroine’ the second Garratt on the Wells & Walsingham Light Railway and is currently working on a completely new Garratt incorporating as much modern practice as possible into a large miniature engine design.

We humbly thank Richard for his invaluable contribution, helping to ensure that this new-build George the Fifth, while a true member of the class and externally indistinguishable from its siblings will nonetheless incorporate the best of modern practice where absolutely critical so that maintenance can be minimised and service-life extended. We aim to build-to-last – an engine that will well outlast us – ensuring many decades of enjoyment for all who see her and ride behind her.

Posted in Fabrication, General News, Research, Richard Coleby, Ted Talbot, Valve Gear, Volunteers | 2 Comments

Those ‘flimsy frames’?

2013? Hard to believe. We hope you are all well and wish you all the best for the coming year. We also hope to have some news for you in the coming weeks now that Christmas is out of the way.

In the meantime we’d like to bring an article written by Ted Talbot for the January edition of ‘Back Track‘ entitled “Centre Bearings, Weak Frames and all that” to your attention. It concerns the removal of the Centre Bearings and frames from LNWR engines, which was authorised in 1923 and had a deleterious effect on the reliability, maintenance costs etc of the engines. Ted’s article looks at the consequences, assesses the reputation that LNWR engines subsequently received, that of having ‘flimsy-frames’ (undeserved argues Ted) and the likely motivations of this removal (a decision emanating from the smoke-filled rooms of Crewe’s old rival, Derby perhaps?)

The Centre Bearing was a feature of LNWR engines employing Joy valve gear where the space on the driving axle typically occupied by the eccentrics driving the steam chests found with Stephensons gear was instead occupied by a centre bearing in addition to the axle box bearings, which served to lessen the fore & aft shocks on the crank axle. To illustrate what a Centre Bearing and frame was, Ted has kindly provided us with a photograph of between the frames on a 5in gauge model of a D class 0-8-0 (the unsuperheated Whale 0-8-0 with large boiler). Note the central plate or frame and the Central Bearing between the connecting rods and cranks. Note too that the steam-chest linkages to the con-rods known as the valve rods and the reverse gear linkages have been removed here for clarity.

We heartedly recommending Ted’s fascinating article. We also recommend the Back Track journal for anyone interested in the rich and endlessly fascinating history of Britain’s railways.

Posted in BackTrack Journal, Fabrication, General News, History, Research, Ted Talbot, Uncategorized, Valve Gear | 1 Comment